feat(cli): cldk query — fluent chain in, JSON out

[rahlk]

cldk console entry point: fluent chain in, JSON out — for agents without a Python runtime, shell pipelines, and CI.

cldk query --lang python --project . "callables().with_decorator('http.route').signatures()"

Scope

• JSON output honors .select() / .limit() projections; --explain includes provenance.
• Exit codes suitable for scripting.

Part of #195. Branch: feat/issue-<n>.